Bidirectional switch with increased switching breakdown voltage

Abstract

A monolithic bidirectional switch formed in a semiconductor substrate of a first conductivity type having a front surface and a rear surface, including a first main vertical thyristor, the rear surface layer of which is of the second conductivity type, a second main vertical thyristor, the rear surface layer of which is of the first conductivity type. A structure for triggering each of the first and second main thyristors is arranged to face regions mutually distant from the two main thyristors, the neighboring portions of which correspond to a region for which, for the first main thyristor, a short-circuit area between cathode and cathode gate is formed.

What is claimed is:  
     
       1. A monolithic bidirectional switch formed in a semiconductor substrate of a first conductivity type having a front surface and a rear surface, including 
       a first main vertical thyristor, the rear surface layer of which is of the second conductivity type,  
       a second main vertical thyristor, the rear surface layer of which is of the first conductivity type, and  
       a triggering structure for each of the first and second main thyristors,  
       wherein said triggering structures are arranged to face regions mutually distant from the two main thyristors, the neighboring portions of which correspond to a region for which, for the first main thyristor, a short-circuit area between cathode and cathode gate is formed.  
     
     
       2. The bidirectional switch of  claim 1 , including: 
       a first auxiliary vertical thyristor, the rear surface layer of which is of the second conductivity type and is common with that of the first main thyristor,  
       a second auxiliary vertical thyristor, the rear surface layer of which is of the second conductivity type and is common with that of the first thyristor, the main upper surface terminals of the first and second auxiliary thyristors forming a same control terminal,  
       a peripheral region of the second conductivity type connecting, in particular, the rear surface layer of the auxiliary thyristors to the gate layers of these auxiliary thyristors located on the other side of the substrate,  
       a first rear surface metallization,  
       a second front surface metallization connecting the front surface regions of the first and second thyristors.  
     
     
       3. The bidirectional switch of  claim 2 , including an additional region that isolates the rear surface of the first auxiliary thyristor from the first metallization. 
     
     
       4. The bidirectional switch of  claim 2 , including, in the substrate between the upper surface of each of the main thyristors and the upper surface of each of the auxiliary thyristors, a region of the first conductivity type more heavily doped than the substrate, connected to the other region.